The present invention relates to scroll machines. More particularly, the present invention relates to a scroll machine having a clearance between the scrolls and the Oldham coupling which allows deflection of the keys of the Oldham coupling.
A class of machines exists in the art generally known as scroll machines which are used for the displacement of various types of fluid. The scroll machines can be configured as an expander, a displacement engine, a pump, a compressor etc. and the features of the present invention are applicable to any one of these machines. For purposes of illustration, however, the disclosed embodiment is in the form of a hermetic refrigerant scroll compressor.
Scroll compressors are becoming more and more popular for use as compressors in both refrigeration as well as air conditioning applications due primarily to their capability for extremely efficient operation. Generally, these machines incorporate a pair of intermeshed spiral wraps, one of which is caused to orbit relative to the other so as to define one or more moving chambers which progressively decrease in size as they travel from an outer suction port toward a center discharge port. An electric motor is provided which operates to drive the orbiting scroll member via a suitable drive shaft affixed to the motor rotor. In a hermetic compressor, the bottom of the hermetic shell normally contains an oil sump for lubricating and cooling purposes.
Relative rotation, between the spiral wraps is typically controlled using an Oldham coupling. The Oldham coupling can be keyed to the main bearing housing and the orbiting scroll member, or the Oldham coupling can be keyed to both the orbiting and the non-orbiting scroll members. The keys of the Oldham coupling are slidingly received within slots of the main bearing housing, the orbiting scroll member or the non-orbiting scroll member. In order to reduce the noise generated during the operation of the scroll compressor, the clearance between the keys of the Oldham coupling and its associated slot should be tightly controlled.
When the clearances between the keys of the Oldham coupling and their associated slots is tightly controlled, binding of the keys within their associated slots can occur during times of heavy loading of the Oldham coupling. This binding of the keys within the slots causes excessive loading of the keys as well as generating excessive noise.
The present invention provides the art with a scroll compressor which includes an Oldham coupling which has both a tight tolerance fit of the keys of the Oldham coupling in their associated slots while simultaneously providing a tapered or stepped surface which provides a clearance between the key and the slot for allowing deflection of the keys of the Oldham coupling. The tapered or stepped surface can be located on the keys of the Oldham coupling or the tapered or stepped surface can be located on the sides of the slots within which the keys slide.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.